Oysters as fish habitat in NSW

Native oysters once formed extensive reefs along temperate Australian coastlines, but less than 10% remain. With the loss of oyster reefs has been the loss of ecosystem services they provide, including provision of food and habitat to fish and invertebrates, shoreline stabilization and, as a consequence of their filter feeding, maintenance of clean water. As awareness of the extent of oyster reef loss has grown, so too has interest in oyster reef restoration. The development of realistic goals for restoration requires knowledge of the services provided by remnant oyster reefs, and the habitat contexts under which these services are maximised.

My PhD is addressing the role of remnant oyster reefs in providing food and habitat to wild fish communities. First, using underwater video surveys, I am comparing the fish communities supported by remnant oyster reefs to those provided by: (1) non reef-forming oysters in mangroves and on rocky shores; (2) other key habitats of the estuarine seascape (seagrass, mangroves, unvegetated sediments); and (3) oyster farms, which provide structure and a source of organic matter. Second, I am using a combination of stable isotope and gut content analyses to determine the trophic role of oyster reefs in estuarine seascapes. Funding provided by the Endowment will support stable isotope analyses.

In combination, video sampling and stable isotope analysis will provide critical information on the role of remnant oyster reefs in supporting wild communities of fish, many of which are recreationally and commercially harvested. The results will contribute to a business case, targeted at recreational fishing groups and fisheries managers, outlining the fisheries benefits of oyster reef restoration.